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101.
Soil Microbial Biomass and Enzyme Activities as Influenced by Organic Manure Incorporation into Soils of a Rice-Rice System 总被引:1,自引:0,他引:1
A fertilizer management study involving incorporation of poultry manure, farm yard manure, sesbania and gliricidia into soils of a rice-rice system was initiated in May 1993. In order to determine the effects of organic manure incorporation on soil microbial biomass and enzyme activity, soils were collected from the respective plots at the end of the second rice crop in February 1996. and were incubated with and without the respective organic manure at the rate of 15 Mg ha−1 at 25°C, under submergence. The total viable microbial counts, bacteria, actinomycetes, N flush, biomass C and activities of urease, amidase, acid and alkaline phosphatase, dehydrogenase and L-glutaminase were determined after 60 days of incubation.
Soils freshly amended and soils previously amended with organic manures registered significantly greater microbial biomass and enzyme activity than the unamended control. The microbial biomass and enzyme activity, however, varied with the type of organic manure incorporated into the soil. Except for acid phosphatase, which showed slight inhibition, all the other enzymes were activated to different degrees by organic manure incorporation. A significant and positive relationship of enzyme activity with organic C and total N suggested that the addition of organic manure to soils increased C turnover, N availability and microbial activity which in turn led to greater enzyme synthesis and accumulation in the soil matrix. 相似文献
Soils freshly amended and soils previously amended with organic manures registered significantly greater microbial biomass and enzyme activity than the unamended control. The microbial biomass and enzyme activity, however, varied with the type of organic manure incorporated into the soil. Except for acid phosphatase, which showed slight inhibition, all the other enzymes were activated to different degrees by organic manure incorporation. A significant and positive relationship of enzyme activity with organic C and total N suggested that the addition of organic manure to soils increased C turnover, N availability and microbial activity which in turn led to greater enzyme synthesis and accumulation in the soil matrix. 相似文献
102.
S. Prakash I. Ahuja H. C. Upreti V. Dinesh Kumar S. R. Bhat P. B. Kirti V. L. Chopra 《Plant Breeding》2001,120(6):479-482
An alloplasmic mustard, Brassica juncea, has been synthesized by placing its nucleus into the cytoplasm of the related wild species Erucastrum canariense to express cytoplasmic male sterility. To achieve this, the sexual hybrid E. canariense (2n=18, EcEc) ×Brassica campestris (2n= 20, AA) was repeatedly backcrossed to B. juncea (2n= 36, AABB). Cytoplasmic male‐sterile (CMS) plants were recovered in the BC4 generation. These plants are a normal green and the flowers have slender, non‐dehiscing anthers that contain sterile pollen. Nectaries are well developed and female fertility is > 90%. The fertility restoration gene was introgressed to CMS B. juncea from the cytoplasmic donor E. canariense through pairing between chromosomes belonging to B. juncea with those of the E. canariense genome. The restorer plants have normal flowers, with well‐developed anthers containing fertile pollen. Meiosis proceeds normally. Pollen and seed fertility averaged 90% and 82%, respectively. F1 hybrids between CMS and the restorer are fully pollen fertile and show normal seed set. Preliminary results indicate that restoration is achieved by a single dominant gene. The constitution of the organelle genomes of the CMS, restorer and fertility restored plants is identical, as revealed by Southern analysis using mitochondrial and chloroplast probes atp A and psb D, respectively. 相似文献
103.
104.
Fixation and defixation of ammonium in soils: a review 总被引:2,自引:0,他引:2
Fixed NH4+ (NH4+
f) and fixation and defixation of NH4+ in soils have been the subject of a number of investigations with conflicting results. The results vary because of differences
in methodology, soil type, mineralogical composition, and agro-climatic conditions. Most investigators have determined NH4+
f using strong oxidizing agents (KOBr or KOH) to remove organic N and the remaining NH4+
f does not necessarily reflect the fraction that is truly available to plants. The content of native NH4+
f in different soils is related to parent material, texture, clay content, clay mineral composition, potassium status of the
soil and K saturation of the interlayers of 2:1 clay minerals, and moisture conditions. Evaluation of the literature shows
that the NH4+
f-N content amounts to 10–90 mg kg−1 in coarse-textured soils (e.g., diluvial sand, red sandstone, granite), 60–270 mg kg−1 in medium-textured soils (loess, marsh, alluvial sediment, basalt) and 90–460 mg kg−1 in fine-textured soils (limestone, clay stone). Variable results on plant availability of NH4+
f are mainly due to the fact that some investigators distinguished between native and recently fixed NH4+ while others did not. Recently fixed NH4+ is available to plants to a greater degree than the native NH4+
f, and soil microflora play an important role in the defixation process. The temporal changes in the content of recently fixed
NH4+ suggest that it is actively involved in N dynamics during a crop growth season. The amounts of NH4+ defixed during a growing season varied greatly within the groups of silty (20–200 kg NH4+-N ha−1 30 cm−1) as well as clayey (40–188 kg NH4+-N ha−1 30 cm−1) soils. The pool of recently fixed NH4+ may therefore be considered in fertilizer management programs for increasing N use efficiency and reducing N losses from
soils. 相似文献
105.
106.
Pratibha Sharma Swati Deep Manika Sharma Dinesh Singh Bhati 《Journal of General Plant Pathology》2013,79(1):41-45
Cauliflower (Brassica oleracea L. var. botrytis) and mustard [Brassica juncea (L.) Czern] are important cruciferous crops facing serious yield and quality loss in India from dark leaf spot disease caused by Alternaria brassicae (Berk.) Sacc. Genetic variation among 32 pathogenic A. brassicae isolates from both crops was analyzed with random amplified polymorphic DNA and inter-simple sequence repeat primers in which the mean similarity coefficient was found to be 0.73 and 0.84, respectively. Further internal transcribed spacer analysis showed all isolates are 90–100 % similar to each other, indicating genetic similarity among different A. brassicae isolates that vary pathogenically. 相似文献
107.
Pallavi Bhardwaj Pritam K. Sidhu Simrat Pal Singh Saini Dinesh M.B. Satyavan Rampal 《Journal of veterinary pharmacology and therapeutics》2019,42(4):430-439
The pharmacokinetics (PK) and pharmacodynamics (PD) of marbofloxacin (MBF) were determined in six healthy female goats of age 1.00–1.25 years after repeated administration of MBF. The MBF was administered intramuscularly (IM) at 2 mg kg?1 day?1 for 5 days. Plasma concentrations of MBF were determined by high‐performance liquid chromatography, and PK parameters were obtained using noncompartmental analysis. The MBF concentrations peaked at 1 hr, and peak concentration (Cmax) was 1.760 µg/ml on day 1 and 1.817 µg/ml on day 5. Repeated dosing of MBF caused no significant change in PK parameters except area under curve (AUC) between day 1 (AUC0–∞D1 = 7.67 ± 0.719 µg × hr/ml) and day 5 (AUC0‐∞D5 = 8.70 ± 0.857 µg × hr/ml). A slight difference in mean residence time between 1st and 5th day of administration and accumulation index (AI = 1.13 ± 0.017) suggested lack of drug accumulation following repeated IM administration up to 5 days. Minimum inhibitory concentration (MIC) demonstrated that Escherichia coli (MIC = 0.04 µg/ml) and Pasturella multocida (MIC = 0.05 µg/ml) were highly sensitive to MBF. Time‐kill kinetics demonstrated rapid and concentration‐dependent activity of MBF against these pathogens. PK/PD integration of data for E. coli and P. multocida, using efficacy indices: Cmax/MIC and AUC0–24hr/MIC, suggested that IM administration of MBF at a dose of 2 mg kg?1 day?1 is appropriate to treat infections caused by E. coli. However, a dose of 5 mg kg?1 day?1 is recommended to treat pneumonia caused by P. multocida in goats. The study indicated that MBF can be used repeatedly at dosage of 2 mg/kg in goats without risk of drug accumulation up to 5 days. 相似文献
108.
109.
Dinesh Fernando Jonas Hafrén Jan Gustafsson Geoffrey Daniel 《Journal of Wood Science》2008,54(2):134-142
Due to the increasing demand for Norway spruce as prime raw material for high-yield pulping, recent interest has focused on
Scots pine as an alternative. However, the intrinsic properties of Scots pine, particularly the high amounts of extractives
and the fiber properties, have been considered a disadvantage for thermomechanical pulping. A study was therefore conducted
on the variations in the spatial distribution and redistribution of lipophilic extractives in spruce and pine wood and thermomechanical
pulp (TMP) using cytochemical staining methods and chemical analysis. Chemical analyses showed chips from pine thinnings and
sawmill slabs to contain three to five and two to three times, respectively, more extractives than found in spruce; in particular,
the amount of triglycerides differed significantly. Results from staining techniques on the abundance and distribution of
extractives (i.e., fats) between pine and spruce correlated with amounts detected by Fourier transform infrared spectroscopy
and gel permeation chromatography. Cytochemical observations revealed information pertaining to species-specific distribution
and redistribution of extractives among TMP fines and fibers and indicated the presence of a molecular film of extractives.
Results indicate that the high concentrations of extractives in pine ray parenchyma are released during TMP processing and
are redistributed onto the surfaces of the pulps, negatively affecting energy usage during primary refining. 相似文献
110.
Three methods of rice cultivation were compared in a field experiment at New Delhi, India during 2012 for their water use and changes in nutrient availability of soil. The experiment was laid out in a split plot design with conventional transplanting (CT), system of rice intensification (SRI), and aerobic rice (AR) cultivation technologies. Five doses of nitrogen included 100 % (120 kg N ha?1), 125, and 150 % recommended dose of N(RDN) through urea, 75 % of RDN through urea (90 kg N ha?1) + 25 % of RDN (30 kg ha?1) through farm yard manure (FYM), and 100 % of RDN through FYM. Results revealed that status of available N in soil under rice at 45 and 90 days after sowing (DAS) was significantly higher in CT and SRI compared to AR method. Application of the highest dose of nitrogen through urea resulted in the highest availability of N (188.9, 174.2, and 135.2 kg ha?1 for 45 and 90 DAS and at harvest stage, respectively). The soil under AR recorded significantly low availability of phosphorus and iron. However, availability of K in soil was not affected significantly under adopted production techniques and nitrogen management. The recorded irrigation water productivity was maximum in AR cultivation (9.16 kg ha mm?1) followed by SRI (7.02 kg ha mm?1) with irrigation water saving of 54 and 36 %, respectively compared to CT. 相似文献